Hedge trimmer



Jan 6, 1931. A. THIBAULT 1,787,802

HEDGE TRIMMER Filed Nov. 1, 1929 2 Sheets-sheet 1 mi. 3, mm

M Wi 55 A. THIBAULT Jah 6, 1931.

HEDGE TRIMMER Filed Nov. 2 Sheets-Sheet 2 Patented Jan. 6, 1931 unisostares;

ADELBERT THIBAU-LT; qr Nnw-Bnnronn,

imssaeziusnms; ASSIGIQOR or one-THIRD TO JEAN B PT'IsTnFo-a'rmannonn'rirannroMAXIM BOIIIN, BOTH on NEW.

BEDFORD, MASSACHUSETTS I ran-nee TnIMMEn Applieationfiled November 1, 1 929. Serial No. 40 4 ,076. h

This invention relates to agricultural. ap e paratus and more particularly to machines of the mowing type especially .forrtrimming" {the knives in different positions;

edge view showing hedgesan-d shrubbery. Y

It is a general object ofthe present invention to provide a novelf and improved device ofthetype mentioned.

a More particularly it is invention to provide a means for reciprocating the-knives of the cutter. bar.

One of vention comprises the important features of the in;

each knife cooperates not only with its mate but with one knife of each ad acent pair so that for each fullstroke of the kmves'each knife makes four cuts, two with itsmate andkni ves. of a the resides in. a novel drive mechanism am,

stroke adjusting mechanism bars of a mower.

for the sickle e Other and. further features and objects of the inventionw ll be more apparent tov those skilled in the art upon a consideration a of the.accompanyingidrawing and following specification wherein is disclosed a single exemplary embodiment of the invention with the understanding that such changes may be made therein as fallwithin the scope of the app ended claims without as parting from the spirit of the invention. L

In said drawing:

Figure 1 is a plan view of ahedge trimmer I according to the present inven-. tion with certain parts broken away to show i terior ie h sm;

Figure 2 is. an edge elevation thereof;

i ligm'etjs a plan view partially broken anobject. of the. hedge trimmer in a which ac'utter bar has directlysecured thereto a power. drivelmechanism associated with novel arrangementof. the knivesjof the cutterbar wherein a plurality thereof are arranged in pairs so that trimming hedges, both sides. being reached with equal facility and together with respectively.

received between the frame members away, of a portion of the cutting knife meeh anlsm and driving linkage; v

Figure e is a view slmllar to Figure 3 with Eigure 5 is an enlarged the kn ves andthelr drlvlng mechanism;

Flgnre 6 is'a' section,

ure e showing the driving eccentrics. Y

The present invention is particularly disclosed-in connection with a. portable or hand type hedge trimmer although it will be appreciated thatcertain features of the inventon areequally applicable. to varioustypes of harvesting and mowing machinery. The present embodiment Ofilll invention provides a. convenient'and lightweightrmechanism' which can be operated by one man for curves and rounded portions being cut with ease.

Referring to the drawings there is dis closed at 10 that portion of the apparztus gencrallytermed acutter bar, at 11 a frame rnction, at 12 the driving motor and at l3 ine speedreitlncing and motion changing mechanism for connecting the motor to the sir-ides of the cutter bar. I

The cutter bar proper is formed from the upper andlower frame members 1% and 15 between them the inner ends of a plurality ofeutter blades 17 which are arranged in cooperating pairs as best seen in Figures.36 inclusive. f 1

Each blade 17 iscomposed of a bar of suitable. metal. rectangular in cross section. About one-half the length of each knife is or plates 14 and-.15. The outer or exposed ends of the the top and vertical These members comprise thin, elongated plates of su table metal spaced apart by spacerrmembers 16 and-carrying new k I on line 6 6 of Fig-' .nrehthrough the cutter bar; and J a Figure v7 1s a section, on line 7 -7 of Fig knives are sharpened to a tapered point by" I cutting away the sides as at 20 and applying the bevels 21 to the upper faces thereof. This provides a blade sharpened to provide the edges. 22 which are not of the knife variety but rather of the shear type and tips. which are not entirely pointed as seen at 23 for the sake of added strength. Each knife has its true cutting edges in the same plane as one,

face thereof and the knives are arranged in pairs with these cuttingface planes together.

Each pair of knives is pivoted together and to the frame plates 14 and 15, between which it fits,by means of admit or pivot member 2;

which passes through theplates andsuitable ward the cutting edges'ofthe-knivesare the sickle bars 26, 27 spaced a sl ght d stance from the front edges, 28 of the frame members.-

These sickle 'bars' are long strips of suitable metal which reston theouter faces of fthe' knives and are pivoted thereto at 30 by suitable pivot members. Each sickle car '15- attached only tofone kn1feofeach'1mir 11111 otherwords, to. all of the knives on one side of the cutting plane which may be defined as the plane lying betweenthe knives of each Dair. As seen in Figure 3 the connections be sickle bars is such that the knives can all be arranged at right angles to, the longitudinal axis ofthe frame and still have the knives of each pair in exact overlapping relation. The close spacing of the knives permits each knife to cut not only with its mate but with the mat s of theknives on each side of it. This is clearly shown in Figure wh ere the knives on one side of the cutting plane have been shifted with their cutting edges in one direction and those on the other side of the plane shifted with their cutting edges in the oppm site direction, this being performed-by oppositely moving sickle bars. Here each knife above the cuttingrplane is shown to be cooperating .witha knife below 'the cutting plane of the bar to its right and v ce versa. It will be seen from this arrangement that starting with the position of the knives shown in Figure 3, moving them to the position of Figure 4, back to the position of Figure 3, to the position directly opposite that of Figure 4, and back to' the position of Figure 3 that ach knife will make four cuts, two with each of its cutting edges, one when that edge en-- gages the opposite cutting edge of its mate, and one when it engages the ad acent cutting edge of the mate of the knife nea rest to it.

The knives are adapted to be moved through the cyclejust described by suitable power means such for instance, as the electric motor 12 which is shown as mounted'at the such as on certain I drills.

site end 48 is pivoted tween the knives, the frame members, and the 0f a-llnk 49,

far end oflthe frame which is'formed by ofisetting the frame members 14 and 15 as shown at 32 and 33 and extending them longitudh nally from the knives. The motor 12 is The motor may conveniently, be provided with a built-in speed reducing mechanism 37 types of portable electric The-extension shaft 38 is secured to the shaft merging from the speed reducing gearing and is journallcd in tl of'a U-shaped bracket 39 attached t the upper surface of the top frame plate 14 on the offset portion thereof, At, the far e'nd'this shaft carries the miter pinion 40 which meshes with the miter wheel 41 mounted on a shaft 42 which passes through the offset portions 32 and 33of botnthe plates 14 and This shaft 42 is formed preferably integral with the pair of eccentrics 43, 44 spaced apart by a centrally disposed disc so that the occentrics lie' against the inner faces of the extensionparts 32 and 33. I 1

J ournalle d on each eccentric is the looped end 1460f an eccentric rod 47 whose oppointermediate the ends the lower end of which is-pivoted at 50 to the end of one of the sickle bars 26, 27; The opposite end of each link 49 is V pivoted-at51 to each of vthe second links 52,

the far ends of which are slotted as at and pass over bolts 54 having heads bearing against the links adjacent the slot and portions passing through the adjacentparts of the frame members with tightening nuts on the outside. i Y

The two eccentrics are disposed 180 apart on the shaft 4:2 :mdby the identical construction of the eccentric rods produce opposi te rcciprocatimi or oscillation of the sickle bars toproduce the cutting effect already described- The linkages fol-connecting the eccentrics to the sickle bars are such as to give the bars a greater movement, in the normaladjustment, than the throw of the eccentric. The range of stroke of the sickle bars and hence of the knives can be regulated to some degree by adjusting the links 52. by loosening the fasteningbdlts 54 and sliding the links to change the positions of the fixed ends 51 of'the links 49 and thus to change the angle-throughwhich these links operate. I

V InFlgures 1 and 2 are slfown the guides 55 secured to and extending out beyond the edgesQS of the frame members, and bearin on the outer facesof the sickle bars to serv as guides and. to assist in holding the sickle bars and thus the knives of each pairtoward J the numbermemos each other to produce an adequate shearing action. 7 a a f The motor may conveniently be provided with a handle of the pistol grip type 56 which can conveniently have a trigger 57' for controlling the flow of current to the motor which is. supplied through the conductor 58. This handle is intended to be grasped by the 'operators left hand while the right hand grasps thehandle 59 which is comprised of a bar or rod extending parallel to the frame members and held by the brackets 60'and 61 above the miter gears;

With the device just described very excellent results can be produced because of of cuts per knife per cycle of operation. By having two sets of knives reciprocating oppositely it is not necessary matter of fact the knives could be mounted solelyjcn the sickle bars and pivoted together at their far ends and would'function in exactly the manner described, but for rigidity it is advisable to have at least one frame member to maintain the pivoted ends of the knife pairs in the same plane iii spite of wear, on the pivots at the sickle bar connections. The whole device is extremely simple in construction-and operation and can be constructed at a low cost.

Having thus described the invention, what is claimed as new and desiredto be secured by Letters Patent is:

1. A cutter bar including in combination, a pair of spaced frame members, a plurality of knives arranged in cooperating pairs spaced from each other along and between said mei'nbers, the inner ends of the knives of each pair being pivoted together and to said members,.one knife of each pair being pivoted intermediate its ends to a sickle bar and the other knife of each pair being similarly pivoted to another sickle bar and means to oscillate said sickle bars oppositely.

2. A cutter bar including in combination, a frame member, a plurality of elongated knives arranged in cooperating pairs spaced along said member, the inner ends of the knives of each pair being pivoted together and to said member, all of the knives on one side of the cutting plane being pivoted intermediate their ends to a sickle bar and those on the opposite'side of theplane being pivoted similarly to a second sickle bar, means to oscillate said sickle bars oppositely and cutting edges on said knives so that each cooperates twice with its mate and once With the mate of each adjacent knife in each full cycle of both sickle bars.

the opposite ends being shar 'iened end thereof,

each other to'cut in the same 3. In aihedge trimmer, in combination, a frame member, Ea plurality of elongated knives arranged in cooperating pairs spaced along said member, the inner ends of the knives of each pair being pivoted together and to said member, all of the knives on one side of the on ting plane being pivoted inter mediatetheir ends toja siclne bar and those on pivoted i sickle bar, a motor mounted at one end of said frame, mechanism the opposite sideof the plane being imi ar y to a s c n associated with said motor tooscillate said sickle bars oppositely and means to adjust the position of each sickle bar in relation to the frame;

4. In a portable hedge trimmer, in combination, a prime mover having a carrying handle 'a frame member eXtendin from said 7 i a pr me mover parallel to the shait thereof, a

plurality 10f elongated knives spaced along said member and extending transversely thereof, thesharpened ends of said'knives ek tending beyond the edge of said nember and pivoted to the member, a sickle bar pivoted to each knife near the sharpened end thereof,'a gear wheel pivoted to said frame member, a cooperatingipinion on, the-prime HIOYGL' shaft, a pitniai driven by ear r-Jlieeha link pivoted atone end" to said sicklebar, said-pitinaiibeing pivoted said link intern' ediate its ends and means to adjust-ably pivot the opposite end of said link to said fran'ie member whereby the range of the stroke of said knives can be regulated. 5.111 a portable hedge trimmer, in C0111- bination, a prime mover having a carrying handle, a frame member extending from sai d prime mover parallel to the shaft thereof, a plurality of elongated knives spaced along said member and extending transversely thereof, the sharpened ends of said knives extending beyond the edge of said member and the opposite ends beiiT pivoted to the memher, a sickle bar pivotec to each knife near the a gear wheel pivoted to said frame member, a cooperating pinion on the prime mover shaft, a pitman driven by said gear wheel, a link pivoted at one end to said sickle bar, said piti'nan being pivoted to said link intermediate its ends, a second link having one end pivoted to the opposite end of said first mentioned link and means to adjustably secure the opposite end of said second link to said frame member;

6. In a cutter bar, in combination, a plurality of long knives eaehhaving a tapered end sharpened on two edges, said knives being arrai'igcd in pairs pivoted together to cut as shears, said pairs being mounted beside plane, the spacing between pairs being such that a knife of one pair can cooperate with its mate and the opposing knives of the adjacent pairs and means to drive the knives at one side of the plane in opposite reciprocations.

pair of -m pairs pivoted to "7.- Ina hedge trimmer, in combination, a

lon knives each having a tapered end sharpened on gether and to said'plates,

the ivoted ends'bein between the slates end-the sharpened ends projecting from be- V seen other cut the pivoted ends tween them, said pairs being arranged beside in the same plane, 9, sickle bar parallel to and beyond each frame plateandeach pivoted to the blades at one side of the plane, means to reciprocate said bars and'ineans to guide said bars to move in the pianos of said plates.

8. In a hedge trimmer, pair of spaced frame plates, a plurality of long knives each having a tapered end sharpened on two edges, said knives beingarranged in pairs pivoted togetherand to said plates, being between the plates, and the sharpened ends projecting frorn'be tween them, said pairsbeingarranged beside each other to out in the same plane, the spacing between pairs being opposing knives of the two adjacent pairs, a sickle bar parallel to each frame plate and each pivoted to aill of the blades atone-side of said cnttingplane, 01' said frame members and mechanism assoc ating said motor and sickle bars to reciprocate them in opposition.

In testimony whereof I hereunto afiix my signature.

I it ADELBERT THIBAU T;

spaced frame plates, a plurality of 7 two edges, said knives being arranged in combination, a 5

such that each lrniie of each pair cooperates at tunes with the a motor carried by one 

